1. Field of the Invention
The invention relates to an electric power supply device that supplies electric power to a plurality of load instruments which are mounted on a vehicle.
2. Description of Related Art
The vehicle described above is provided with a battery that is charged by an electric power generator. A device in which a lead storage battery is electrically connected in parallel to an electric power storage device having a plurality of electric double layer capacitors has been proposed as an example of this type of devices. According to Japanese Patent Application Publication No. 2012-240593, a first path that allows a high-load instrument with a relatively large electrical load capacity, such as a starter and a power steering device, to be electrically connected to the electric power storage device via a DC/DC converter, a second path that allows the high-load instrument to be electrically connected to the electric power storage device not via a DC/DC converter, and a switch that turns ON/OFF each of the first path and the second path are disposed. Also, a technique has been disclosed in which electric power is supplied to the high-load instrument by using the first path when the load of the DC/DC converter is within the range of tolerance and electric power is supplied to the high-load instrument by using the second path, with the first path OFF, when the load of the DC/DC converter is equal to or greater than the tolerance so that the DC/DC converter and the second path are protected.